The large-scale organization of Baroque confraternal life in the Diocese of Eger was initiated by Bishop Ferenc Barkóczy, who established the Confraternity of the Blessed Sacrament—already well known throughout the Catholic world at that time—in Eger, in 1757. His work was continued with great enthusiasm by Bishop Károly Eszterházy, who embraced the initiative and introduced this type of confraternity throughout the diocese in order to promote the greatest possible and constant veneration of the Eucharist.
The most important sources for studying the membership of Baroque confraternities are the membership registers, in which the personal data of individuals entering the confraternity were recorded. Unfortunately, these confraternal registers have survived only in very rare cases. During the state confiscation of the assets of confraternities in the second half of the 1780s, these registers were, in principle, to be surrendered to the state treasury, after which they—together with other religious items—faced destruction or, in a better case, sale or disposal. Most of those that remain survived the past two centuries only thanks to their secondary reuse in other contexts. At present, eight membership registers of Confraternities of the Blessed Sacrament are known from the territory of the Diocese of Eger: the registers from Egerszalók, Csernely, Diósgyőr, Gyöngyössolymos, Jászárokszállás, Kunszentmárton, and the central confraternity in Eger (the Barkóczy Album), as well as the diarium of the confraternity of the Episcopal School in Eger, which includes a list of its members. These sources allow us to learn about the size and gender composition of the membership, the dynamics of the confraternity’s development, and the evolution of its catchment area—in other words, several aspects of the functioning of Baroque religious confraternities that previous research has only rarely examined.